1. Field of the Invention:
The invention relates to CATV systems, and more particularly, to a method and apparatus, for the jamming, in a multi-tiered fashion, and on a time shared basis, of selected channels, to selected subscribers.
2. Description of Related Art:
CATV systems, in which there are a number of channels provided to the subscribers, are well known. Many CATV systems, charge different amounts to their various subscribers, depending on how many of the supplied channels the particular subscriber wants to receive. The basic TV channels (hereinafter, in this disclosure, and the claims, referred to as "BTV channels") generally refers to the channels automatically received when a person subscribes. The extended basic TV channels (hereinafter, in this disclosure, and the claims, referred to as "EBTV channels") generally refers to the channels a subscriber pays an additional fee to receive, on a per channel, or on a per group of channels, basis. CATV systems, offering between fifteen and thirty channels, and sometimes more, are available in many jurisdictions. Some of those channels, are BTV channels, and some are EBTV channels. A result of the large number of channels currently available through CATV systems, is that there are many instances, in which it would be desirable, to have the capability, to be able to selectively jam, up to twenty-four selected channels, to selected subscribers.
The inventors are not aware of any prior art multi-tier systems. The prior art systems, presently known to the inventors, generally consist of generating up to eight different jamming signals, sometimes continuously, and sometimes on a time divisional basis. In some present art systems, each continuously generated jamming signal, is continuously added, to the line, of each subscriber, that is not permitted to view the particular channel it jams. In some present art systems, the continuously generated jamming signals, are added on a time shared bases, to the lines of the subscribers, that are not permitted to view the particular channel being jammed. In some present art systems, the time divisionaly generated jamming signals, are added on a time shared basis, to the subscribers lines, who are not permitted to view the particular channel being jammed.